draft-ietf-spring-segment-routing-central-epe-07.txt   draft-ietf-spring-segment-routing-central-epe-08.txt 
Network Working Group C. Filsfils, Ed. Network Working Group C. Filsfils, Ed.
Internet-Draft S. Previdi Internet-Draft S. Previdi
Intended status: Informational G. Dawra, Ed. Intended status: Informational G. Dawra, Ed.
Expires: May 1, 2018 Cisco Systems, Inc. Expires: June 21, 2018 Cisco Systems, Inc.
E. Aries E. Aries
Juniper Networks Juniper Networks
D. Afanasiev D. Afanasiev
Yandex Yandex
October 28, 2017 December 18, 2017
Segment Routing Centralized BGP Egress Peer Engineering Segment Routing Centralized BGP Egress Peer Engineering
draft-ietf-spring-segment-routing-central-epe-07 draft-ietf-spring-segment-routing-central-epe-08
Abstract Abstract
Segment Routing (SR) leverages source routing. A node steers a Segment Routing (SR) leverages source routing. A node steers a
packet through a controlled set of instructions, called segments, by packet through a controlled set of instructions, called segments, by
prepending the packet with an SR header. A segment can represent any prepending the packet with an SR header. A segment can represent any
instruction topological or service-based. SR allows to enforce a instruction topological or service-based. SR allows to enforce a
flow through any topological path while maintaining per-flow state flow through any topological path while maintaining per-flow state
only at the ingress node of the SR domain. only at the ingress node of the SR domain.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 1, 2018. This Internet-Draft will expire on June 21, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction 1. Introduction
The document is structured as follows: The document is structured as follows:
o Section 1 states the BGP-EPE problem statement and provides the o Section 1 states the BGP-EPE problem statement and provides the
key references. key references.
o Section 2 defines the different BGP Peering Segments and the o Section 2 defines the different BGP Peering Segments and the
semantic associated to them. semantic associated to them.
o Section 3 describes the automated allocation of BGP Peering SID's o Section 3 describes the automated allocation of BGP Peering
by the BGP-EPE enabled egress border router and the automated Segment-IDs (SIDs) by the BGP-EPE enabled egress border router and
signaling of the external peering topology and the related BGP the automated signaling of the external peering topology and the
Peering SID's to the collector related BGP Peering SID's to the collector
[I-D.ietf-idr-bgpls-segment-routing-epe]. [I-D.ietf-idr-bgpls-segment-routing-epe].
o Section 4 overviews the components of a centralized BGP-EPE o Section 4 overviews the components of a centralized BGP-EPE
controller. The definition of the BGP-EPE controller is outside controller. The definition of the BGP-EPE controller is outside
the scope of this document. the scope of this document.
o Section 5 overviews the methods that could be used by the o Section 5 overviews the methods that could be used by the
centralized BGP-EPE controller to implement a BGP-EPE policy at an centralized BGP-EPE controller to implement a BGP-EPE policy at an
ingress border router or at a source host within the domain. The ingress border router or at a source host within the domain. The
exhaustive definition of all the means to program an BGP-EPE input exhaustive definition of all the means to program an BGP-EPE input
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Internet routes are assumed to use IPv4 unlabeled or IPv6 Internet routes are assumed to use IPv4 unlabeled or IPv6
unlabeled. It is not required to place the Internet routes in a unlabeled. It is not required to place the Internet routes in a
VRF and allocate labels on a per route, or on a per-path basis. VRF and allocate labels on a per route, or on a per-path basis.
o The solution MUST support any deployed iBGP schemes (RRs, o The solution MUST support any deployed iBGP schemes (RRs,
confederations or iBGP full meshes). confederations or iBGP full meshes).
o The solution MUST be applicable to both routers with external and o The solution MUST be applicable to both routers with external and
internal peers. internal peers.
o The solution SHOULD minimize the need for new BGP capabilities at o The solution should minimize the need for new BGP capabilities at
the ingress PEs. the ingress PEs.
o The solution MUST accommodate an ingress BGP-EPE policy at an o The solution MUST accommodate an ingress BGP-EPE policy at an
ingress PE or directly at a source host within the domain. ingress PE or directly at a source within the domain.
o The solution MAY support automated Fast Reroute (FRR) and fast o The solution MAY support automated Fast Reroute (FRR) and fast
convergence mechanisms. convergence mechanisms.
The following reference diagram is used throughout this document. The following reference diagram is used throughout this document.
+---------+ +------+ +---------+ +------+
| | | | | | | |
| H B------D G | H B------D G
| | +---/| AS 2 |\ +------+ | | +---/| AS 2 |\ +------+
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C is configured with local policy that defines a BGP PeerSet as the C is configured with local policy that defines a BGP PeerSet as the
set of peers (2001:db8:ce::e for E and 2001:db8:f::f for F) set of peers (2001:db8:ce::e for E and 2001:db8:f::f for F)
X is the BGP-EPE controller within AS1 domain. X is the BGP-EPE controller within AS1 domain.
H is a content source within AS1 domain. H is a content source within AS1 domain.
2. BGP Peering Segments 2. BGP Peering Segments
As defined in [I-D.ietf-spring-segment-routing], certain segments are As defined in [I-D.ietf-spring-segment-routing], certain segments are
defined by BGP-EPE capable node and corresponding to its attached defined by a BGP-EPE capable node and corresponding to its attached
peers. These segments are called BGP peering segments or BGP Peering peers. These segments are called BGP peering segments or BGP Peering
SIDs. They enable the expression of source-routed inter-domain SIDs. They enable the expression of source-routed inter-domain
paths. paths.
An ingress border router of an AS may compose a list of segments to An ingress border router of an AS may compose a list of segments to
steer a flow along a selected path within the AS, towards a selected steer a flow along a selected path within the AS, towards a selected
egress border router C of the AS and through a specific peer. At egress border router C of the AS and through a specific peer. At
minimum, a BGP Egress Peering Engineering policy applied at an minimum, a BGP Egress Peering Engineering policy applied at an
ingress EPE involves two segments: the Node SID of the chosen egress ingress EPE involves two segments: the Node SID of the chosen egress
EPE and then the BGP Peering Segment for the chosen egress EPE peer EPE and then the BGP Peering Segment for the chosen egress EPE peer
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3.2. PeerNode SID to E 3.2. PeerNode SID to E
Descriptors: Descriptors:
o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)): o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)):
192.0.2.3, AS1, 1000 192.0.2.3, AS1, 1000
o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.5, AS3 o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.5, AS3
o Link Descriptors (IP interface address, neighbor IP address): o Link Descriptors (IPv6 Interface Address, IPv6 Neighbor Address):
2001:db8:ce::c, 2001:db8:ce::e 2001:db8:ce::c, 2001:db8:ce::e
Attributes: Attributes:
o PeerNode SID: 1022 o PeerNode SID: 1022
o PeerSetSID: 1060 o PeerSetSID: 1060
o Link Attributes: see section 3.3.2 of [RFC7752] o Link Attributes: see section 3.3.2 of [RFC7752]
3.3. PeerNode SID to F 3.3. PeerNode SID to F
Descriptors: Descriptors:
o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)): o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)):
192.0.2.3, AS1, 1000 192.0.2.3, AS1, 1000
o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.6, AS3 o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.6, AS3
o Link Descriptors (IP interface address, neighbor IP address): o Link Descriptors (IPv6 Interface Address, IPv6 Neighbor Address):
2001:db8:c::c, 2001:db8:f::f 2001:db8:c::c, 2001:db8:f::f
Attributes: Attributes:
o PeerNode SID: 1052 o PeerNode SID: 1052
o PeerSetSID: 1060 o PeerSetSID: 1060
3.4. First PeerAdj to F 3.4. First PeerAdj to F
Descriptors: Descriptors:
o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)): o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)):
192.0.2.3, AS1, 1000 192.0.2.3, AS1, 1000
o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.6, AS3 o Remote Node Descriptors (BGP router-ID, ASN): 192.0.2.6, AS3
o Link Descriptors (IP interface address, neighbor IP address): o Link Descriptors (IPv6 Interface Address, IPv6 Neighbor Address):
2001:db8:cf1::c, 2001:db8:cf1::f 2001:db8:cf1::c, 2001:db8:cf1::f
Attributes: Attributes:
o PeerAdj-SID: 1032 o PeerAdj-SID: 1032
o LinkAttributes: see section 3.3.2 of [RFC7752] o LinkAttributes: see section 3.3.2 of [RFC7752]
3.5. Second PeerAdj to F 3.5. Second PeerAdj to F
Descriptors: Descriptors:
o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)): o Local Node Descriptors (BGP router-ID, ASN, BGP-LS Identifier)):
192.0.2.3 , AS1 192.0.2.3 , AS1
o Remote Node Descriptors (peer router-ID, peer ASN): 192.0.2.6, AS3 o Remote Node Descriptors (peer router-ID, peer ASN): 192.0.2.6, AS3
o Link Descriptors (IP interface address, neighbor IP address): o Link Descriptors (IPv6 Interface Address, IPv6 Neighbor Address):
2001:db8:cf2::c, 2001:db8:cf2::f 2001:db8:cf2::c, 2001:db8:cf2::f
Attributes: Attributes:
o PeerAdj-SID: 1042 o PeerAdj-SID: 1042
o LinkAttributes: see section 3.3.2 of [RFC7752] o LinkAttributes: see section 3.3.2 of [RFC7752]
3.6. Fast Reroute (FRR) 3.6. Fast Reroute (FRR)
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The BGP-EPE controller might collect the traffic matrix to its peers The BGP-EPE controller might collect the traffic matrix to its peers
or the final destinations. IPFIX [RFC7011] is a likely option. or the final destinations. IPFIX [RFC7011] is a likely option.
An alternative option consists in collecting the link utilization An alternative option consists in collecting the link utilization
statistics of each of the internal and external links, also available statistics of each of the internal and external links, also available
in the current definition of [RFC7752]. in the current definition of [RFC7752].
4.6. Business Policies 4.6. Business Policies
The BGP-EPE controller should be configured or collect (through any The BGP-EPE controller should be configured or collect business
mean) business policies. The mechanisms through which these policies policies through any desired mechanisms. These mechanisms by which
are configured or collected is outside the scope of this document. these policies are configured or collected are outside the scope of
this document.
4.7. BGP-EPE Policy 4.7. BGP-EPE Policy
On the basis of all these inputs (and likely others), the BGP-EPE On the basis of all these inputs (and likely others), the BGP-EPE
Controller decides to steer some demands away from their best BGP Controller decides to steer some demands away from their best BGP
path. path.
The BGP-EPE policy is likely expressed as a two-entry segment list The BGP-EPE policy is likely expressed as a two-entry segment list
where the first element is the IGP prefix SID of the selected egress where the first element is the IGP prefix SID of the selected egress
border router and the second element is a BGP Peering SID at the border router and the second element is a BGP Peering SID at the
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o Other static or ephemeral APIs o Other static or ephemeral APIs
Example: at router A (Figure 1). Example: at router A (Figure 1).
Tunnel T1: push {64, 1042} Tunnel T1: push {64, 1042}
IP route L/8 set next-hop T1 IP route L/8 set next-hop T1
5.3. At a Router - RFC3107 policy route 5.3. At a Router - RFC3107 policy route
The BGP-EPE Controller could build a RFC3107 The BGP-EPE Controller could build a RFC3107 ([RFC8277]) route (from
([I-D.ietf-mpls-rfc3107bis]) route (from scratch) and send it to the scratch) and send it to the ingress router:
ingress router:
o NLRI: the destination prefix to engineer: e.g., L/8. o NLRI: the destination prefix to engineer: e.g., L/8.
o Next-Hop: the selected egress border router: C. o Next-Hop: the selected egress border router: C.
o Label: the selected egress peer: 1042. o Label: the selected egress peer: 1042.
o AS path: reflecting the selected valid AS path. o AS path: reflecting the selected valid AS path.
o Some BGP policy to ensure it will be selected as best by the o Some BGP policy to ensure it will be selected as best by the
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9. Manageability Considerations 9. Manageability Considerations
The BGP-EPE use-case described in this document requires BGP-LS The BGP-EPE use-case described in this document requires BGP-LS
([RFC7752]) extensions that are described in ([RFC7752]) extensions that are described in
[I-D.ietf-idr-bgpls-segment-routing-epe]. The required extensions [I-D.ietf-idr-bgpls-segment-routing-epe]. The required extensions
consists of additional BGP-LS descriptors and TLVs that will follow consists of additional BGP-LS descriptors and TLVs that will follow
the same. Manageability functions of BGP-LS, described in [RFC7752] the same. Manageability functions of BGP-LS, described in [RFC7752]
also apply to the extensions required by the EPE use-case. also apply to the extensions required by the EPE use-case.
The operator MUST be capable of configuring, enabling, disabling the Additional Manageability considerations are described in
advertisement of the EPE information as well as to control which [I-D.ietf-idr-bgpls-segment-routing-epe].
information is advertised to which internal or external peer. This
is not different from what is required by a BGP speaker in terms of
information origination and advertisement.
10. Security Considerations 10. Security Considerations
[RFC7752] defines BGP-LS NLRIs and their associated security aspects. [RFC7752] defines BGP-LS NLRIs and their associated security aspects.
[I-D.ietf-idr-bgpls-segment-routing-epe] defines the BGP-LS [I-D.ietf-idr-bgpls-segment-routing-epe] defines the BGP-LS
extensions required by the BGP-EPE mechanisms described in this extensions required by the BGP-EPE mechanisms described in this
document. BGP-EPE BGP-LS extensions also include the related document. BGP-EPE BGP-LS extensions also include the related
security. security.
skipping to change at page 17, line 31 skipping to change at page 17, line 31
13.2. Informative References 13.2. Informative References
[I-D.ietf-idr-te-pm-bgp] [I-D.ietf-idr-te-pm-bgp]
Ginsberg, L., Previdi, S., Wu, Q., Gredler, H., Ray, S., Ginsberg, L., Previdi, S., Wu, Q., Gredler, H., Ray, S.,
Tantsura, J., and C. Filsfils, "BGP-LS Advertisement of Tantsura, J., and C. Filsfils, "BGP-LS Advertisement of
IGP Traffic Engineering Performance Metric Extensions", IGP Traffic Engineering Performance Metric Extensions",
draft-ietf-idr-te-pm-bgp-08 (work in progress), August draft-ietf-idr-te-pm-bgp-08 (work in progress), August
2017. 2017.
[I-D.ietf-mpls-rfc3107bis]
Rosen, E., "Using BGP to Bind MPLS Labels to Address
Prefixes", draft-ietf-mpls-rfc3107bis-04 (work in
progress), August 2017.
[I-D.ietf-pce-pce-initiated-lsp] [I-D.ietf-pce-pce-initiated-lsp]
Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
Extensions for PCE-initiated LSP Setup in a Stateful PCE Extensions for PCE-initiated LSP Setup in a Stateful PCE
Model", draft-ietf-pce-pce-initiated-lsp-11 (work in Model", draft-ietf-pce-pce-initiated-lsp-11 (work in
progress), October 2017. progress), October 2017.
[I-D.ietf-pce-segment-routing] [I-D.ietf-pce-segment-routing]
Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "PCEP Extensions for Segment Routing", and J. Hardwick, "PCEP Extensions for Segment Routing",
draft-ietf-pce-segment-routing-10 (work in progress), draft-ietf-pce-segment-routing-11 (work in progress),
October 2017. November 2017.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>. <https://www.rfc-editor.org/info/rfc6241>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken, [RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX) "Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77, Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013, RFC 7011, DOI 10.17487/RFC7011, September 2013,
skipping to change at page 18, line 32 skipping to change at page 18, line 26
Litkowski, S., Horneffer, M., and R. Shakir, "Source Litkowski, S., Horneffer, M., and R. Shakir, "Source
Packet Routing in Networking (SPRING) Problem Statement Packet Routing in Networking (SPRING) Problem Statement
and Requirements", RFC 7855, DOI 10.17487/RFC7855, May and Requirements", RFC 7855, DOI 10.17487/RFC7855, May
2016, <https://www.rfc-editor.org/info/rfc7855>. 2016, <https://www.rfc-editor.org/info/rfc7855>.
[RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder, [RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder,
"Advertisement of Multiple Paths in BGP", RFC 7911, "Advertisement of Multiple Paths in BGP", RFC 7911,
DOI 10.17487/RFC7911, July 2016, DOI 10.17487/RFC7911, July 2016,
<https://www.rfc-editor.org/info/rfc7911>. <https://www.rfc-editor.org/info/rfc7911>.
[RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address
Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
<https://www.rfc-editor.org/info/rfc8277>.
Authors' Addresses Authors' Addresses
Clarence Filsfils (editor) Clarence Filsfils (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
Brussels Brussels
BE BE
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Stefano Previdi Stefano Previdi
skipping to change at page 19, line 4 skipping to change at page 18, line 44
Brussels Brussels
BE BE
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Stefano Previdi Stefano Previdi
Cisco Systems, Inc. Cisco Systems, Inc.
Italy Italy
Email: stefano@previdi.net Email: stefano@previdi.net
Gaurav Dawra (editor) Gaurav Dawra (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
USA USA
Email: gdawra@cisco.com Email: gdawra.ietf@gmail.com
Ebben Aries Ebben Aries
Juniper Networks Juniper Networks
1133 Innovation Way 1133 Innovation Way
Sunnyvale CA 94089 Sunnyvale CA 94089
US US
Email: exa@juniper.net Email: exa@juniper.net
Dmitry Afanasiev Dmitry Afanasiev
Yandex Yandex
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